System and Method for Seamless Mobility in a Network Environment

ABSTRACT

In one example, an apparatus is provided that includes a processor configured to receive, in a first wireless network, an identifier of a base station in a second wireless network, and to determine an identity of a first device in the second wireless network. The apparatus is configured to transmit the identifier of the base station to the second wireless network.

CROSS-REFERENCE TO RELATED APPLICATION

Application is a continuation and claims the benefit of priority under35 U.S.C. §120 of U.S. application Ser. No. 14/160,127, filed Jan. 21,2014, entitled “SYSTEM AND METHOD FOR SEAMLESS MOBILITY IN A NETWORKENVIRONMENT,” Inventors Mukesh Taneja, et al., which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

This disclosure relates in general to the field of telecommunicationsand, more particularly, to providing seamless mobility in a networkenvironment.

BACKGROUND

Some wireless products are based on the Institute of Electrical andElectronics Engineers' (IEEE) 802.11 standards (WiFi), whereas othersuse a cellular network. There have been many activities in thecellular-Wi-Fi integration area in the past few years. Cellular (e.g.,Long Term Evolution [LTE]/3G) and WiFi networks can be integrated via aloose coupling or a tighter coupling. Some work has offered mechanismsthat consider a loose coupling of LTE and WiFi networks. Proxy MIPv6 isan example in which a loose coupling of LTE and Wi-Fi networks isconsidered. There is an interest to move towards a tighter couplingnetwork architectures, as these architectures can provide a moreseamless mobility experience to users. For example, some companies haveproposed to include tighter coupling of LTE-WiFi networks for 3GPPRelease 12.

There are many constraints in supporting dual mode LTE-WiFi UserEquipment (UE) (e.g., a handset). One constraint is that the cost of thehandset goes up: for example, supporting two RF chips increases the costof device. There are also interference issues that need to be tackledwhen LTE as well as WiFi RF are active on the same device, especially ifthey are on similar RF frequencies (e.g., 2.4 GHz/2.3 GHz). There arealso battery issues when two RF chains are active simultaneously, andone is communicating data over two radio access technologies. There aredevices that support two RF chips (one for cellular and one for Wi-Fi),but only one is active at a time due to these issues. On the other end,there are more expensive devices that support two active RF chips, butthat support is typically for select spectrum bands only.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying figures, whereinlike reference numerals represent like parts, in which:

FIG. 1 illustrates a system architecture in which a long-term evolution(LTE)→wireless local area network (WLAN) handover can be implemented;

FIGS. 2A-2B illustrate a view of potential operations in a high levelapproach for an LTE->WLAN handover;

FIGS. 3A-3B illustrate another view of potential operations in a highlevel approach for an LTE->WLAN handover;

FIG. 4 illustrates an example of an enhanced beacon that can be receivedby the UE from the WLAN AP at S210;

FIG. 5 illustrates an example of an enhanced probe response that can bereceived by the UE from the WLAN AP at S210;

FIG. 6 illustrates a system architecture in which a WLAN→LTE handovercan be implemented;

FIG. 7 illustrates a view of potential operations in a high levelapproach for a WLAN→LTE handover;

FIG. 8 illustrates another view of potential operations in a high levelapproach for a WLAN→LTE handover;

FIG. 9 illustrates an example of the 802.11 MAC message that can betransmitted from the UE to the WLAN AP at S715;

FIG. 10 illustrates an example of the type and subtype field of theframe control field of the IEEE 802.11 MAC frame shown in FIG. 9; and

FIG. 11 illustrates an example computer system that can be used torealize the devices of the LTE and WLAN systems.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

In one example, an apparatus is provided that includes a processorconfigured to receive, in a first wireless network, an identifier of abase station in a second wireless network, and to determine an identityof a first device in the second wireless network. The apparatus isconfigured to transmit the identifier of the base station to the secondwireless network.

In other more specific embodiments, the processor is configured todetermine the identity of the first device based at least in part on theidentifier of the base station and a location of a device in the firstwireless network. In yet other embodiments, the processor is configuredto determine the identity of the first device based at least in part onmapping information. The apparatus can be configured to transmit to thefirst device a Quality of Service (QoS) parameter of a session in thefirst network. The apparatus can also be configured to contact the firstdevice in the second wireless network via a tunnel, to receive anidentity of a second device in the second wireless network, and toestablish a tunnel with the second device. In yet other examples, theapparatus is configured to receive a first indication whether a handoverfrom the first wireless network to the second wireless network isaccepted. Additionally, the apparatus can be configured to transmit asecond indication in the first wireless network that the handover isaccepted and to stop a transmission of data in the first wirelessnetwork after transmitting the second indication.

In another example, one or more computer readable storage media areprovided. The one or more computer readable storage media are encodedwith software comprising computer executable instructions and, when thesoftware is executed, operable to perform a method including receiving,in a first wireless network, an identifier of a base station in a secondwireless network; determining an identity of a first device in thesecond wireless network; and transmitting the identifier of the basestation to the second wireless network.

In a further example, a method is provided and includes receiving, in afirst wireless network, an identifier of a base station in a secondwireless network; determining an identity of a first device in thesecond wireless network; and transmitting the identifier of the basestation to the second wireless network.

EXAMPLE EMBODIMENTS Example Implementations Involving LTE→WLAN Handover

Embodiments provide mobility methods for a seamless handover between,for example, long-term evolution (LTE) and wireless local area network(WLAN) networks. Some embodiments provide methods that work when thereis only one active radio frequency (RF) chip at a time in a user device(e.g., tunable RF to cover two radio access technologies (RATs)). Amethod is also specified for the case where a device (e.g., userequipment (UE)) can communicate with the LTE network, as well as theWLAN network simultaneously. Embodiments can include a mobility methodfor a device with two RF chips but only active chip at a time, and amobility method for a device with two RF chips where both can be usedsimultaneously for control information but only one is used for datacommunication. Some methods also establish an IPsec tunnel from the UEto do the handover, though an IPsec tunnel from the UE is notestablished in some cases.

Methods provided herein can help to achieve a make-before-breakhandover, as a dual mode LTE-WLAN UE is allowed to carry out mechanismssuch as a selection of a suitable WLAN AP for a handover from an LTEeNodeB to a WLAN AP, assisting an LTE network in identifying a WLANAccess Gateway (AGW) that is acting as a WLAN AGW for the selected WLANAP, an association with the WLAN AP, and an authentication for a WLANnetwork while the UE continues to communicate data with the LTE network.Unlike other methods, closer integration of the LTE and the WLANnetworks is made feasible by providing a logical interface tunnelbetween a MME (mobility management entity of an LTE core network,Evolved Packet Core [EPC]) and a WLAN AGW. Methods are specified so thateven devices with only one active RF at a time (i.e., either an LTE RFor a WLAN RF is active at a time but not both simultaneously) canachieve a make-before-break handover.

A make-before-break handover method is also provided for a WLAN→LTEhandover. For preparing for such a handover, no IPsec tunnel needs to beestablished from the user equipment, and IEEE 802.11 MAC messages,CAPWAP, and S1-AP protocol messages can be enhanced to carry handovermessages. Several initial LTE related operations are completed duringinitial handover preparation.

FIG. 1 illustrates an example system architecture 100 to which anembodiment for handing over from an LTE network to a WLAN network can beapplied. In the illustrated embodiment, the system can include a PDNGateway (P-GW) connected to a Policy and Charging Rules Function (PCRF),an SGi interface, an S2a interface, and an S5 interface (as per 3GPPTS23.402). The P-GW connects to a WLAN AGW by the S2a interface andconnects to an S-GW node by the S5 interface. The S-GW node is connectedto a MME and an LTE eNodeB. The eNodeB is, for example, an LTE basestation. The MME is connected to a Home Subscriber Server (HSS)connected to Authentication, Authorization, and Accounting (AAA). TheWLAN AGW is connected to the AAA, as well as a Wireless LAN Controller(WLC) and a WLAN access point (AP). In one scenario, communication isperformed WLAN AGW-WLC-WLAN AP. In another scenario, communication isperformed WLAN AGW-WLAN AP.

FIGS. 2A-2B and 3 illustrate potential operations in a high-levelapproach for an LTE→WLAN handover. At the initial point of the flow, theUE is attached to the LTE network having used LTE procedures, and datais being communicated between the UE and the Internet via the P-GW.During these operations, data communication continues between the UE andthe LTE network via LTE access technology, unless otherwise noted. Theoperations begin at S200 and proceed to S205 to prepare for handover.

At S205, a MAC scheduler at the eNodeB notifies the UE of schedulinggaps using a Radio Resource Control (RRC) Connection Reconfigurationmessage. RRC is specified in 3GPP TS 36.331 and is a control planeprotocol.

The scheduling gaps refer to periods during which the LTE datatransmissions are suspended. In one embodiment, the RRC message asks theUE to measure the signal strength of APs, including WLAN APs, using anAbstract Syntax Notation One (ASN.1) segment. Conventional RRC protocoldoes not allow an LTE eNodeB to explicitly ask user equipment to measurethe signaling strength of WLAN APs. In addition, the enhanced RRCmessage can indicate a duration of a gap (e.g., in milliseconds).

At S210, the UE receives a signal transmitted from a WLAN AP during atleast one of the scheduling gaps provided by the eNodeB in S205. Thissignal includes a MAC address of the WLAN AP in, for example, a basicservice set identification (BSSID) or source address (SA) field. Thissignal also includes a location of the WLAN AP and an SSID of the WLANAP.

In one implementation of S210, the signal is any suitable beacon signalfrom the WLAN AP. This beacon signal can be enhanced, for example,relative to an existing IEEE 802.11 beacon signal, as described later.In another implementation, the signal is any suitable probe response.This probe response can be enhanced relative to an existing IEEE 802.11signal, as described later. The probe response can be received after theUE sends a probe request message to the WLAN AP prior to S210, forexample, in response to a determination that one of the scheduling gapshas begun. Typically, the probe response is received by the UE duringthe same scheduling gap. However, it is possible, though less desirable,for the probe response to be received by the UE after the conclusion ofthe scheduling gap or during a later scheduling gap. In such a case, theUE can send a subsequent probe request before the beginning of ascheduling gap to attempt to receive the probe response during ascheduling gap.

The UE sending a probe request message to the WLAN AP, rather thanreceiving a beacon signal therefrom, can be advantageously implementedwhen a delay between consecutive beacon signals is high. Because theWLAN AP sends the probe response message in response to receiving theprobe request message, the UE can receive the signal at S210 without adelay associated with waiting for the WLAN AP to transmit a next beacon.Thus, the UE can more quickly receive a signal from the WLAN AP.

At S215, the UE measures a signal strength of the signal received atS210.

At S220, the UE selects a WLAN. In one embodiment, the UE determineseach WLAN AP having a received signal strength above a threshold. Inembodiments in which a signal is received from a single WLAN AP at S210,the determination is based on comparing the signal strength against apredetermined threshold. In embodiments in which multiple signals arereceived from multiple WLAN APs at S210, the signal strengths mayalternatively (or additionally) be compared against each other, suchthat the UE can determine a WLAN AP having a highest signal strength. Inaddition, the UE can determined the WLAN AP using policies such as usinga WLAN AP from a preferred operator of the UE or using a WLAN AP thatuses a preferred WLAN AGW of the UE.

The UE informs the LTE eNodeB about parameters of the selected WLAN APvia an enhanced RRC measurement report message at S225. The WLANparameters can include the signal strength of the WLAN AP measured bythe UE, the MAC address of the WLAN AP, the SSID of the WLAN AP, thelocation of the UE (measured via GPS or 3GPP techniques), and thelocation of the WLAN AP as provided in the signal received at S210. TheWLAN parameters can additionally include the IP or MAC address(es) ofthe WLAN AGW or the WLC if provided or other parameters for the WLAN APextracted from the signal received at S210.

At S230, the eNodeB conveys a handover request to the MME. The handoverrequest can be or include a source-to-target container. Thissource-to-target container can include quality of service (QoS)requirements of LTE radio bearers to be handed over from the LTE networkto the WLAN network (for example, but not necessarily limited to, theeNodeB), the location of the WLAN AP, the MAC address of the WLAN AP,the SSID of the WLAN AP, and the location of the UE. Thesource-to-target container can additionally include vendor specificparameters if included in the probe response or beacon received at S210.

Further, the source-to-target container can include the IP address ofthe target WLAN AGW, particularly if the same is included in the proberesponse or beacon received at S210. In addition, the source-to-targetcontainer can include an authentication object for the WLAN network. Theauthentication object can be included, for example, when the LTE networkand the WLAN network belong to the same operator or have a trustrelationship.

The source-to-target container can be conveyed from the LTE eNodeB tothe MME via an enhanced S1-AP protocol, a Stream Control TransmissionProtocol (SCTP), or IPsec. S1-AP is specified in 3GPP TS 36.413 and is acontrol plane protocol. S1-AP is generally used for message passingbetween the eNodeB and the MME.

At S235, the MME transmits the handover request (e.g., thesource-to-target container) to a node in the WLAN network via a logicalLTE_WLAN Handover (LWH) interface. The handover request can includeinformation about existing flows and/or applications at the UE. The nodecan be a target WLAN AGW (e.g., a controller, such as an ASR1000 orASR9000 type of node), if an IP address of the target WLAN AGW wascommunicated by the UE. If the MME does not receive an IP address of a(target) WLAN AGW, the MME transmits the handover request to an IPaddress of a default WLAN AGW configured at the MME. The default WLANAGW then determines the target WLAN AGW based on the location of theWLAN AP, the MAC address of the WLAN AP, and, in some embodiments, thelocation of the UE. The default WLAN AGW then forwards the handoverrequest to the target WLAN AGW.

In an embodiment in which the WLC serves a large number of APs or if theUE communicates an IP address of the WLC, the node is the WLC. Further,the node can also be the WLAN AP. This disclosure will be writtenassuming the node is a WLAN AGW.

The LWH interface can use a simple message transfer protocol. As S1-APis already standardized in 3GPP, a very light version of S1-AP,S1-AP-Lite, can be used as the simple message transfer protocol over anIPsec tunnel. This handover request reduces interruption time, as thehandover is make-before-break.

S1-AP-Lite is used in communications between the MME and the WLAN AGWand between the WLAN AGW and the WLC. The S1-AP format is used, but theobjects are only those that are described in this disclosure, such asthe source-to-target container: other eNodeB-MME objects given in 3GPPTS36.413 are generally not part of S1-AP-Lite.

The WLAN AGW (e.g., an Intelligent Services Gateway (ISG) or a BroadbandNetwork Gateway (BNG) executing thereon) keeps mapping information in adatabase to identify the WLAN AP or the WLC, given the location or theMAC address of the WLAN AP. This mapping information includes locationsand MAC addresses of APs that are reachable from the WLAN AGW.

The WLAN AGW then determines the WLC communicating with the WLAN AP andsends a handover request to the WLC via a simple message transferprotocol. In one embodiment, the simple message transfer protocol usedbetween the WLAN AGW and the WLC is S1-AP-Lite. In another embodiment,the simple message transfer protocol used between the WLAN AGW and theWLC is an enhanced version of CAPWAP.

The handover request sent by the WLAN AGW includes an identification ofthe WLAN AP, an authentication object if provided in thesource-to-target container, and the QoS requirements of the LTE bearersto be handed over to the WLAN network. The WLAN AGW checks to see if thepolicies of the WLAN AP allow for service of the UE. The WLC thentransmits a handover request to the WLAN AP at S240. This handoverrequest includes the QoS requirements of the LTE bearers (DRBs).

The LTE data bearers carry data for the UE; thus, the UE has multipleDRBs across the LTE network (e.g. a UE having three applications canhave three DRBs going through UE-eNodeB-SGW-PGW). These DRBs cancorrespond to one or multiple access point names (APNs) (e.g., a UEhaving one DRB with PGW1 going through UE-eNodeB-SGW-PGW1 and anotherDRB with PGW2 going through UE-eNodeB-SGW-PGW2). Information about(ideally, all) the DRBs is communicated from the LTE network to the WLANnetwork during handover preparation, such as beginning with thesource-to-target container transmitted by the eNodeB. This informationincludes QoS requirements of each DRB, an APN ID, an IP address of theP-GW, etc. In some embodiments, the MME supplements or otherwisemodifies the information received from the eNodeB to reflect a DRB.

In many embodiments, all DRBs to which resources are allocated in theLTE network are handed over to the WLAN network during the handoverprocess. For example, the P-GW switches its data path from P-GW-S-GW-LTEeNodeB-UE to P-GW-WLAN AGW-WLC-WLAN AP-UE.

Thus, during handover preparation, the WLAN AGW checks whether or notthe WLAN AGW and the WLAN network can allocate resources to handover theLTE DRBs to the WLAN network at S240. The WLAN AGW, the WLC, and theWLAN AP reserve resources (e.g., if policies for the UE allow suchreservation) for flows that are to be handed over from the LTE networkto the WLAN network. The WLAN AP can transmit to the WLC a confirmationif the handover is approved. Of course, embodiments are possible inwhich the WLAN AP sends a response only if the handover is not approved.

At S245, the WLC (or, in some embodiments in which the WLAN AP does notsend a response to the WLC at S240, the WLAN AP) transmits an LTE-WLANInter-RAT Handover Response to the WLAN AGW via S1-AP-Lite or any simplemessage transfer protocol. The Handover Response includes an IP address(e.g., the IP address of the WLC) to which the LTE eNodeB can create anIPsec tunnel, and an indication as to whether the WLC or WLAN AP canaccept each of the LTE DRBs for handover. Although the WLC IP addressand the LTE DRB acceptance indication are described separately, in someembodiments, the WLC IP address itself indicates whether the LTE DRBscan be accepted. For example, the WLC IP address can indicate the LTEDRBs are not accepted, if the WLC IP address is a predefined address(such as a loopback address) or if the WLC IP address falls outside ofan expected range or inside of a range known to be invalid.

At S250, the WLAN AGW transmits a handover acceptance or failure messageto the MME via the S1-AP-Lite protocol. At S255, the MME transmits anLTE-WLAN Inter-RAT Handover Response to the eNodeB via S1-AP. At S260,the LTE eNodeB establishes an IPsec tunnel to a WLAN node for handoverpurposes. This tunnel can be established to the WLAN AP, to the WLC, orto the WLAN AGW, based on an IP address transmitted from the WLAN AGW tothe MME. For deployment purposes, it is easy to establish the IPsectunnel from the LTE eNodeB to the WLAN AGW. The IPsec tunnel can beestablished to the WLC in a case where the WLC supports a large numberof APs. Establishing the IPsec tunnel to the WLAN AP is suitable forhigh capacity, thick APs (as thin or low capacity APs do not supportIPsec in general). If the processing power of the WLAN AP is limited,the IPsec tunnel can be established to the WLC or WLAN AGW.

The LTE eNodeB then asks the UE to start handover preparation via an RRCmessage (e.g., Handover from EUTRA Preparation Request at S265). If theUE has only one active RF chip at a time, then WLAN association messagesare routed via the LTE network, and RRC can be enhanced for thispurpose. Thus, the UE transmits at S267 an RRC Inter-RAT message WLANAssociation Request to the eNodeB. The WLAN Association Request includesa WLAN AP ID (e.g., MAC address).

In embodiments in which an IPsec tunnel is established between the LTEeNodeB and the WLAN AGW, the eNodeB transmits an Inter-RAT TransparentContainer WLAN Association Request to the WLAN AGW. This WLANAssociation Request transmitted by the eNodeB can include the WLAN APID. The WLAN AGW can then transmit to the WLC a WLAN Association Requestvia S1-AP-Lite over an IPsec tunnel. The WLC can transmit to the WLAN APa WLAN Association Request via enhanced CAPWAP. The WLAN AP responds tothe WLC with a WLAN Association Response via CAPWAP. The WLC transmitsto the WLAN AGW a WLAN Association Response. The WLAN AGW can transmitto the LTE eNodeB an Inter-RAT transparent container via S1-AP-Lite. TheInter-RAT transparent container includes a WLAN Association Response anda WLAN AP ID. The LTE eNodeB transmits to the UE an Inter-RAT messagevia RRC. This Inter-RAT message includes the WLAN Association Responseand the WLAN AP ID.

In embodiments in which an IPsec tunnel is established between the LTEeNodeB and the WLC, the eNodeB transmits an Inter-RAT message to the WLCvia S1-AP-Lite and the IPsec tunnel. The inter-RAT message includes aWLAN Association Request and a WLAN AP ID. The WLC can transmit to theWLAN AP a WLAN Association Request via enhanced CAPWAP. The WLAN APresponds to the WLC with a WLAN Association Response via CAPWAP. The WLCtransmits to the LTE eNodeB an Inter-RAT message. This Inter-RAT messageincludes a WLAN Association Response and a WLAN AP ID. The LTE eNodeBtransmits to the UE an Inter-RAT message via RRC. This Inter-RAT messageincludes the WLAN Association Response and the WLAN AP ID.

Thus, the UE can perform mutual association for the WLAN network via theLTE network at S270, using enhanced RRC/S1-AP messages. In the WiFinetwork, the UE should associate with the WLAN AP. Current systems letthe UE handover from an LTE network to a WiFi network and performassociation in the WiFi network after the handover. Further, currentsystems support WiFi association exchange between the UE, the WLAN AP,and the WLC.

In some implementations of the present disclosure, the UE performs WiFiassociation before actually handing over from the LTE network to theWiFi network. The UE keeps communicating data via the LTE network, andthe UE can exchange WiFi association messages via the LTE network. Insome embodiments, the WiFi association messages are carried from the UE,to the LTE eNodeB, to the WLAN AGW, to the WLC, and finally to the WLANAP. Therefore, the UE can perform WiFi association before actuallyhanding over to WiFi and, during this period, communication via LTEnetwork continues. In that sense, some embodiments can reduce handovertransition time.

After WiFi association, the UE performs authentication in the WiFinetwork at S275 via the LTE network. This authentication can be used ina scenario in which it is not possible to authenticate using AuthObject(as in IEEE 802.11r) and a new round of authentication is used in theWLAN network. A node in the WLAN network (e.g., the WLAN AGW, the WLC,or the WLAN AP) performs Extensible Authentication Protocol for GSMSubscriber Identity Module (EAP-SIM) for the WLAN network with the AAA.The authentication can be performed with the LTE eNodeB using S1-AP-Litemessages and with the UE using enhanced RRC messages. Thus, like theassociation, WiFi authentication messages are routed via the LTEnetwork. By so routing the messages, the UE can be authenticated forWiFi before actually handing over to the WLAN network.

At S280, the MME asks the P-GW to stop sending downlink data to the SGWfor the UE, and the eNodeB sends the UE an RRC message to handover tothe WLAN. The MME asks the P-GW to send data for the UE to the WLAN AGW,and the eNodeB forwards buffered data to a node (e.g., the WLAN AGW, theWLC, or the WLAN AP) in the WLAN network. The UE confirms handover withthe WLAN AP at S285. The UE is synchronized to the WLAN network, anddata communication by the UE via the WLAN network is started at S290.This is because authentication and resource reservation have alreadybeen performed. Thus, a Make-Before-Break handover results. The processends at S295.

FIG. 4 shows an example of the beacon that can be received by the UEfrom the WLAN AP at S210. FIG. 5 shows an example of the probe responsethat can be received by the UE from the WLAN AP at S210. The beacon andprobe response messages can include vendor specific fields that areenhancements to these messages over existing IEEE 802.11 specifications:the location of the WLAN AP and the IP address of the WLAN AGW are notsent in a beacon message under the current IEEE 802.11 standard. Thevendors can be, for example, cellular telephone service providers orequipment manufacturers.

One of the vendor specific fields includes a location of the WLAN AP.This location can be configured at the WLAN AP or obtained via a GPSchip at the WLAN AP. Several LTE/3G-WLAN multimode APs are expected tohave a GPS chip in them. Another vendor specific field includes a MACaddress of the WLAN AP, if the MAC address differs from an address usedby the BSSID in the 802.11 frame (e.g., in the header).

In some embodiments, the beacon and probe response messages includeadditional vendor specific fields. For example, one additional vendorspecific field can include or otherwise indicate an IP address of a WLANAGW with which the WLAN AP communicates, if available at the AP. Anadditional vendor specific field can include or otherwise indicate an IPor MAC address of a WLC with which the WLAN AP communicates, ifavailable at the AP. Note that an AP can communicate with multipleWLC(s). Each AP can be configured with an IP address of its WLAN AGW ora default WLC for this purpose.

WLAN→LTE Handover

FIG. 6 illustrates a system architecture in which a WLAN→LTE handovercan be implemented. FIGS. 7-8 illustrate potential operations in ahigh-level approach for a WLAN→LTE handover. During these operations,data communicates between the UE and the Internet via the P-GW.Specifically, prior to the handover, the data flow begins at the P-GW,and proceeds to the WLAN AGW, to the WLC, to the WLAN AP, and to the UE.The UE continues data transmission via the WLAN network, until otherwisenoted. Generally, LTE messages are sent via the WLAN network to preparefor handover.

The operations begin at S700 and proceed to S705 at which, during ashort idle period, the UE measures the signal strength of an LTE AP(e.g., an eNodeB) and performs an initial synchronization to decode theLTE eNodeB identity at S710.

At S715, the UE informs the WLAN AGW about the LTE eNodeB. Specifically,the UE conveys, to the WLAN AGW, LTE eNodeB parameters (e.g., the signalstrength of the LTE eNodeB, an LTE eNodeB identification (ID), an LTE UEID), a location of the UE, etc.

In some implementations, the UE informs the WLAN AGW by firsttransmitting an enhanced 802.11 MAC message to the WLAN AP. Such animplementation is typically used when it is not desired to create anIPsec tunnel from the UE. In this case, encryption is performed betweenthe UE and the WLAN AP via IEEE 802.11 methods. As discussed later, thetype of the frame control field of the 802.11 MAC message can be set to01, and the subtype can be set to 0000. After the WLAN AP receives this802.11 MAC message, the WLAN AP transmits a message to the WLC viaenhanced CAPWAP, and the WLC transmits a message to the WLAN AGW viaS1-AP-Lite. In this case, TLS or IPsec can be used for security.

In another embodiment, this informing is done via an IPsec tunnel. Inthis case as well, TLS or IPsec can be used for security.

At S720, the WLAN AGW determines an MME to be contacted, and, at S725,the WLAN AGW transmits parameters to an MME. The MME determined in S720need not be the same as the MME to which the parameters are transmittedin S725, as explained below. In one embodiment, the WLAN AGW determinesa target MME based on the LTE eNodeB parameters (e.g., the eNodeB ID)and the location of the UE provided by the UE.

In another case, the parameters and the location of the UE do notidentify the MME, and the WLAN AGW instead contacts a default MME. TheWLAN AGW determines the identity of this default MME based on mappinginformation kept in a database accessible by the WLAN AGW. The WLAN AGWcontacts the default MME via an IPsec tunnel and provides parameters(e.g., the eNodeB ID). The default MME determines the target MME for theeNodeB based on the eNodeB ID or, in some embodiments, the location ofthe UE, the ID of the LTE eNodeB, and/or the location of the LTE eNodeB.The default MME then informs the WLAN AGW of the identity of the targetMME. The WLAN AGW then establishes a tunnel with the target MME to carryout the actual handover of the UE from the WLAN AGW to the target LTEeNodeB controlled by that target MME.

In another scenario, the WLAN AGW determines the default MME andcommunicates with the default MME via a tunnel. The default MME thendetermines the target MME and forwards a handover message to the targetMME.

Typically, MMEs are deployed in pools. For example, one operator mighthave a set of MMEs in a pool, another operator might have another set ofMMEs in another pool, and so on. If the default MME and the target MMEare part of the same pool, the WLAN AGW can simply keep communicatingwith the default MME, which will take care of communication with thetarget MME. If the default MME and the target MME are part of differentpools, the default MME transmits the identity of the target MME to theWLAN AGW. In a way, the WLAN AGW contacts a server to know the identityof the target MME, where the server could be a database server or adefault MME.

The WLAN AGW conveys, at S725, parameters to the target MME over an LWHinterface via an IPsec tunnel using an S1-AP-Lite protocol. In oneembodiment, the conveyed parameters include the UE ID, the LTE eNodeBID, QoS requirements of WLAN sessions, and PGW IP addresses/APN IDs. Ofcourse, as detailed previously, the WLAN AGW need not establish theIPsec tunnel specifically to the target MME: in at least one embodiment,the WLAN AGW establishes an IPsec tunnel to the default MME, and thedefault MME conveys these parameters to the target MME.

At S730, the MME checks for resources in the LTE network for WLANsessions. The MME does a conventional procedure for handover preparationwhile treating the WLAN as another 3GPP-like access technology. Forexample, the MME sends a handover message to the LTE eNodeB via S1-AP.The MME also establishes tunnels between the PGW and the SGW and betweenthe SGW and the eNodeB. In the case that an IPsec tunnel from the UE isnot desired (e.g., in the case that the UE transmitted an 802.11 MACmessage to the WLAN AP for handover preparation), if WLAN sessions to behanded over correspond to multiple APNs, multiple such tunnels arecreated. The eNodeB determines whether to accept the handover andresponds to the MME via S1-AP, SCTP, or IPsec at S735.

At S740, the MME informs the WLAN AGW about whether the eNodeB acceptedthe handover. Specifically, if the handover is not accepted, the WLANAGW then informs the UE and the process ends. If the handover isaccepted, the MME provides to the WLAN AGW a source-to-target containerproviding LTE parameters to aid in LTE access and synchronization (suchas a reserved RACH preamble—as in 3GPP for initial sync). The MME can soinform the WLAN AGW over an LWH interface via an IPsec tunnel usingS1-AP-Lite.

At S745, the WLAN AGW informs the UE about whether the eNodeB acceptedthe handover. In the case that an IPsec tunnel from the UE is notdesired (e.g., in the case that the UE previously transmitted an 802.11MAC message to the WLAN AP for handover preparation), the WLAN AGWconfirms the handover with the UE via an IEEE 802.11 MAC message. Insome embodiments, the WLAN AGW informs the WLC about the acceptance ofthe handover, the WLC then informs the WLAN AP about the acceptance, andthe WLAN AP transmits the 802.11 MAC message to the UE. As discussedlater, the type of the frame control field of the 802.11 MAC message canbe set to 01, and the subtype can be set to 0010.

In the case the UE informed the WLAN AGW of parameters via an IPsectunnel in S715, the WLAN AGW informs the UE, via an IPsec tunnel usingan S1-AP-Lite protocol, that the eNodeB accepted the handover. The UEthen performs authentication at S750 with the LTE network via the WLANnetwork using enhanced 802.11 MAC messages.

Subsequently, the WLAN AGW then stops sending data to the UE at S755,and the data communication via WLAN access stops. In someimplementations, the WLAN AGW forwards buffered data to the P-GW. TheP-GW starts sending data to the SGW instead of the WLAN AGW.

The UE syncs up with the LTE eNodeB at S760 and uses the parametersprovided in the source-to-target container for a fast sync-up. The UEthen starts communicating using the LTE access at S765. The process endsat S770. Following the handover, the data flow is from the P-GW, to theS-GW, to the LTE eNodeB, to the UE.

FIG. 9 illustrates an example of the 802.11 MAC message transmitted bythe UE to the WLAN AP in some implementations of S715. In particular,FIG. 9 shows a MAC frame format, including a frame control field (2bytes), a duration ID field (2 bytes), a field for address 1 (e.g., DA)(6 bytes), a field for address 2 (e.g., SA) (6 bytes), a field foraddress 3 (e.g., BSSID) (6 bytes), a sequence control field foridentifying message order and eliminating duplicate frames (2 bytes), afield for address 4 (optional) (6 bytes), a QoS control field (2 bytes),a frame body (0-2312 bytes), and a frame check sequence field (4 bytes).

FIG. 9 also shows the MAC frame control field includes a protocolversion field (2 bits), a type field (2 bits), a subtype field (4 bits),a To DS (distribution system) field (1 bit), a From DS field (1 bit), amore fragments field (1 bit), a retry field (1 bit), a power managementfield (1 bit), a more data field (1 bit), a protected frame field (1bit), and an order field (1 bit).

FIG. 10 illustrates a use of the type and the subtype field of the framecontrol field of the IEEE 802.11 MAC frame. Specifically, control type01 and subtype 0000-0111 are currently reserved and are not being usedby WLAN control messages. Thus, some embodiments of the presentdisclosure use a portion of that block for WLAN→LTE handoverpreparation.

As shown in FIG. 10, subtype 0000 is used for a WLAN→LTE handoverrequest message sent in, for example, S715. This request message is sentfrom the UE to the WLAN AP to convey the signal strength of the LTEeNodeB, a location of the UE, the LTE eNodeB ID, and the LTE UE ID.Subtype 0001 is used for an acknowledgement (ACK). Subtype 0010 is usedfor a WLAN→LTE handover confirm message sent from the WLAN AP to the UEsuch as in, for example, S745.

In terms of the UE discussed herein, the UEs can be any apparatusassociated with clients or customers wishing to initiate a communicationin system architecture 100 via some network. The term ‘apparatus’ isinterchangeable with the terminology ‘endpoint’ and ‘user equipment(UE)’, where such terms are inclusive of devices used to initiate acommunication, such as a computer, a personal digital assistant (PDA), alaptop or electronic notebook, a cellular telephone, an i-Phone, ani-Pad, a Google Droid, an IP phone, or any other device, component,element, or object capable of initiating voice, audio, video, media, ordata exchanges within system architecture 100.

The apparatus may also be inclusive of a suitable interface to the humanuser, such as a microphone, a display, a keyboard, or other terminalequipment. The apparatus may also be any device that seeks to initiate acommunication on behalf of another entity or element, such as a program,a database, or any other component, device, element, or object capableof initiating an exchange within system architecture 100. Data, as usedherein in this document, refers to any type of numeric, voice, video, orscript data, or any type of source or object code, or any other suitableinformation in any appropriate format that may be communicated from onepoint to another. The apparatus can be able to communicate wirelesslyusing a macro service. As the apparatus is moved from one location toanother, a hand off can be made between network elements (or to macrocell towers), enabling the user to experience continuous communicationcapabilities.

Each P-GW, S-GW, LTE eNodeB, WLAN AGW, MME, WLC, and/or WLAN AP canperform actions in order to offer suitable connectivity to one or morewireless devices using any appropriate protocol or technique. Forexample, in general terms, each WLAN AP represents an access pointdevice that can allow wireless devices to connect to a wired networkusing Wi-Fi, Bluetooth, WiMAX, UMTS, or any other appropriate standard.Hence, the broad term ‘access point’ is inclusive of any wireless accesspoint (WAP), a femtocell, a hotspot, a picocell, a Wi-Fi array, awireless bridge (e.g., between networks sharing same Service SetIdentifier (SSID) and radio channel), a wireless local area network(LAN), or any other suitable access device, which may be capable ofproviding suitable connectivity to a wireless device. In certain cases,the access point connects to a router (via a wired network), and it canrelay data between the wireless devices and wired devices of thenetwork.

In one example implementation, the P-GW, S-GW, LTE eNodeB, WLAN AGW,MME, WLC, and/or WLAN AP are network elements that facilitate orotherwise help coordinate the seamless mobility activities discussedherein (e.g., for networks such as those illustrated in FIG. 1). As usedherein in this Specification, the term ‘network element’ isinterchangeable with ‘apparatus’ and, further, is meant to encompassnetwork appliances, servers, routers, switches, gateways, bridges,loadbalancers, firewalls, processors, modules, base stations, or anyother suitable device, component, element, or object operable toexchange information in a network environment. Moreover, the networkelements may include any suitable hardware, software, components,modules, interfaces, or objects that facilitate the operations thereof.This may be inclusive of appropriate algorithms and communicationprotocols that allow for the effective exchange of data or information.

In one example implementation, P-GW, S-GW, LTE eNodeB, WLAN AGW, UE,MME, WLC, and/or WLAN AP include software to achieve the seamlessmobility operations, as outlined herein in this document. In otherembodiments, this feature may be provided external to these elements, orincluded in some other network device to achieve this intendedfunctionality. Alternatively, both elements include software (orreciprocating software) that can coordinate in order to achieve theoperations, as outlined herein. In still other embodiments, one or bothof these devices may include any suitable algorithms, hardware,software, components, modules, interfaces, or objects that facilitatethe operations thereof.

In regards to the internal structure associated with system architecture100, each of P-GW, S-GW, LTE eNodeB, WLAN AGW, UE, MME, WLC, and/or WLANAP can include memory elements for storing information to be used inachieving the seamless mobility operations, as outlined herein.Additionally, each of these devices may include a processor that canexecute software or an algorithm to perform the seamless mobilityactivities as discussed in this Specification. These devices may furtherkeep information in any suitable memory element [random access memory(RAM), read only memory (ROM), an erasable programmable read only memory(EPROM), an electrically erasable programmable ROM (EEPROM), etc.],software, hardware, or in any other suitable component, device, element,or object where appropriate and based on particular needs. Any of thememory items discussed herein should be construed as being encompassedwithin the broad term ‘memory element.’ The information being tracked orsent to P-GW, S-GW, LTE eNodeB, WLAN AGW, UE, MME, WLC, and/or WLAN APcould be provided in any database, register, control list, cache, orstorage structure: all of which can be referenced at any suitabletimeframe. Any such storage options may be included within the broadterm ‘memory element’ as used herein in this Specification. Similarly,any of the potential processing elements, modules, and machinesdescribed in this Specification should be construed as being encompassedwithin the broad term ‘processor.’ Each of the network elements andmobile nodes can also include suitable interfaces for receiving,transmitting, and/or otherwise communicating data or information in anetwork environment.

Note that in certain example implementations, the seamless mobilityfunctions outlined herein may be implemented by logic encoded in one ormore tangible media (e.g., embedded logic provided in an applicationspecific integrated circuit [ASIC], digital signal processor [DSP]instructions, software [potentially inclusive of object code and sourcecode] to be executed by a processor, or other similar machine, etc.). Insome of these instances, memory elements can store data used for theoperations described herein. This includes the memory elements beingable to store software, logic, code, or processor instructions that areexecuted to carry out the activities described in this Specification. Aprocessor can execute any type of instructions associated with the datato achieve the operations detailed herein in this Specification. In oneexample, the processors could transform an element or an article (e.g.,data) from one state or thing to another state or thing. In anotherexample, the seamless mobility activities outlined herein may beimplemented with fixed logic or programmable logic (e.g.,software/computer instructions executed by a processor) and the elementsidentified herein could be some type of a programmable processor,programmable digital logic (e.g., a field programmable gate array[FPGA], an EPROM, an EEPROM) or an ASIC that includes digital logic,software, code, electronic instructions, or any suitable combinationthereof.

Note that with the examples provided above, as well as numerous otherexamples provided herein, interaction may be described in terms of two,three, or four network elements. However, this has been done forpurposes of clarity and example only. In certain cases, it may be easierto describe one or more of the functionalities of a given set of flowsby only referencing a limited number of network elements. It should beappreciated that system architecture 100 (and its teachings) are readilyscalable and further can accommodate a large number of components, aswell as more complicated/sophisticated arrangements and configurations.Accordingly, the examples provided should not limit the scope or inhibitthe broad teachings of system architecture 100 as potentially applied toa myriad of other architectures.

It is also important to note that the previously described activitiesillustrate only some of the possible signaling scenarios and patternsthat may be executed by, or within, system architecture 100. Some ofthese steps may be deleted or removed where appropriate, or these stepsmay be modified or changed considerably without departing from the scopeof the present disclosure. In addition, a number of these operationshave been described as being executed concurrently with, or in parallelto, one or more additional operations. However, the timing of theseoperations may be altered considerably. The preceding operational flowshave been offered for purposes of example and discussion. Substantialflexibility is provided by system architecture 100 in that any suitablearrangements, chronologies, configurations, and timing mechanisms may beprovided without departing from the teachings of the present disclosure.

LTE-WLAN Handover when the UE can Access the LTE and WLAN NetworksSimultaneously

The previous mobility methods deal with scenarios where the UE canaccess exclusively one of the LTE or WiFi at a time. This sectionextends those methods for the scenario where the UE can access the LTEnetwork as well as the WiFi network simultaneously. The UE in this casedoes not need to be synchronized to the WLAN network via the LTEnetwork, unlike the one RF chip case.

The method begins when the UE is attached to the LTE network having usedLTE procedures, and data is communicated between the UE and the Internetvia the LTE network and, specifically, the P-GW. At the same time, theUE continues to monitor WiFi messages. The LTE eNodeB asks the UE tomeasure the signal strength of neighboring WLAN access points. The UEreceives a signal from a WLAN AP and gets a MAC address of the WLAN AP,a location of the WLAN AP, and SSID of the WLAN AP from the signal.

The LTE network then uses the identity information (e.g., the MACaddress, the location) of the WLAN AP to reserve resources in the WLANnetwork for existing applications of the LTE-WiFi UE that are active onthe LTE network. In one embodiment, the operations specified inS225-S265 are used for this purpose.

In this scenario, association and authentication, similar to theoperations specified in S270-S275, can happen via the WLAN networkitself as the UE can access both networks simultaneously. Once resourcesare reserved, the LTE eNodeB sends a handover command to the UE askingthe UE to handover to the WiFi network, similar to the operationsspecified with regard to S285. The network then switches datatransmission from the LTE network to the WLAN network, and the UE handsover to the WLAN network. This handover is similar to the operationsspecified with regard to S290.

FIG. 11 illustrates an example computer system that can be used torealize the devices of the LTE and WLAN systems. More particularly, FIG.11 illustrates an embodiment of a device 1100 that can be included inany portion (or shared by portions) of the P-GW, the PCRF, the WLAN AGW,the S-GW, the MME, the LTE eNodeB, the HSS, the AAA, the UE, and theWLC.

The device 1100 includes one or more processor(s) 1104, a bus 1106,system memory 1108, non-volatile memory 1110, volatile memory 1114, adisplay controller 1112, a display device 1132 coupled to displaycontroller 1112, wired communication interface(s) 1120, wirelesscommunication interface(s) 1140, and user input device 1102. The variouselements of device 1100 are typically coupled to each other through bus1106, though additional or alternative connections are possible.

Bus 1106, in a particular embodiment, includes a controller to providean interface to the one or more processor(s) 1104 and/or to anycomponent in device 1100. Bus 1106, in a particular embodiment, includesa memory controller to provide an interface to system memory 1108.System memory 1108 can store data and/or instructions, such as software1126. System memory 1108 is or includes dynamic random access memory(DRAM) or SDRAM, for example.

Bus 1106, in a particular embodiment, includes one or more input/output(I/O) controllers to provide an interface to display device 1132,non-volatile memory 1110, a user input device 1102 (e.g., a keyboard, amouse, a joystick, a trackball, a glove, a microphone, a camera, acamcorder, and/or a scanner), a speaker, or a printer.

Non-volatile memory 1110 can store data and/or instructions, forexample, within software 1128. Non-volatile memory 1110 can includeflash memory, for example, and/or non-volatile storage device(s), suchas a magnetic disk, an optical disc, or a magneto-optical disc. Amagnetic disk can be, for example, a hard disk drive (HDD) or a floppydisk. A optical disc can be, for example, a compact disc (CD), a digitalversatile disc (DVD), or a Blu-Ray disc (BD). A magneto-optical disc canbe, for example, a Mini-Disc (MD).

Wired communications interface(s) 1120 can provide an interface fordevice 1100 to communicate over one or more wired networks with anyother device. Wired communications interface(s) 1120 can include anysuitable hardware and/or firmware. Wired communications interface(s)1120, in particular embodiments, includes, for example, a networkadapter or a telephone modem. The wired communications interface(s) 1120are an example of a wired communication means.

Wireless communications interface(s) 1140 can provide an interface fordevice 1100 to communicate over one or more wireless networks with anyother device. These networks can include, but are not limited to, LTEand WiFi. Wireless communications interface(s) 1140 can include anysuitable hardware and/or firmware. Wireless communications interface(s)1140, in a particular embodiment, includes, for example, a wirelessnetwork adapter and/or a wireless modem. The wireless communicationsinterface(s) 1140 are an example of a wireless communication means.

For one embodiment, at least one processor 1104 is packaged togetherwith logic for one or more controllers of bus 1106 to form a System inPackage (SIP). For a particular embodiment, at least one processor 1104is integrated on the same die with logic for one or more controllers ofbus 1106 to form a System on Chip (SoC).

At least one processor 1104 in one embodiment can execute software toprocess information received over wired communication interface 1120 orwireless communication interface 1140. Thus, the one or moreprocessor(s) can execute the operations described in this disclosure,particularly those described in the algorithms of FIGS. 2A-2B, FIGS.3A-3B, and FIGS. 7-8. Such software can include, for example, driversoftware and/or application software. The one or more processor(s) 1104are an example of a processing means.

The software processed by the one or more processor(s) 1104 can bestored on a transitory computer-readable medium or a non-transitorycomputer-readable medium. A transitory computer-readable mediumincludes, for example, a propagating wave or signal, or software itself.A non-transitory computer-readable medium includes any memory of systemmemory 608 or non-volatile memory 610. Both the transitorycomputer-readable medium and the non-transitory computer-readable mediumare examples of a storing means. A transitory storing means can bedistinguished from a non-transitory storing means as described abovewith regard to the media. These media can store instructions that, whenexecuted, cause the one or more processor(s) to execute the operationsdescribed in this disclosure, particularly those described in thealgorithms of FIGS. 2A-2B, FIGS. 3A-3B, and FIGS. 7-8. These media canalso store the data structures described with reference to FIGS. 4-5 andFIGS. 9-10.

The software processed by the one or more processor(s) 1104 can also beexecuted after being downloaded and installed. As is known in the caseof software on a CD or DVD (e.g., a non-transitory computer-readablemedium), the software executed might not be the same as the softwaredownloaded. Thus, a server can store software that, when installed bythe device 1100, causes the device to execute the operations of thepresent disclosure.

Certain example embodiments of the present disclosure can enjoy anynumber of advantages. For example, a system and a method can perform amake-before-break handover for LTE→WLAN (and vice versa) even when theuser device supports only one active RF at a time. In addition, thesystem and method work for the case when two RF devices are active atthe same time and provide for tighter integration even in that case.Performing a make-before-break handover can provide for a more seamlesshandover.

In certain embodiments, the system and the method can provide for atighter coupling between the LTE and the WLAN networks, resulting in aLTE→WLAN handover user experience similar to LTE-3G (HSPA+) handover.For LTE→WLAN handover, overhead over the air interface can be kept lowby enhancing RRC and not necessarily using an IPsec tunnel from the UEover the air interface. For WLAN→LTE handover, IEEE802.11 MAC messagescan be enhanced for handover preparation phase, and no IPsec tunnel isnecessarily established from the UE. Additionally, certain objects canbe added in a WLAN beacon that helps to achieve thismake-before-handover. Note that any number of 3GPP companies aresearching for seamless LTE-WLAN handover solutions as part of 3GPP R12.

Possible Example Modifications for One or More AlternativeImplementations

In the description of LTE→WLAN handover described above, the eNodeBnotifies the UE of scheduling gaps at S205. In some implementations,such a notification might not be performed. For example, a UE withactive concurrent RFs/paths (i.e., one for LTE and another for WiFi)might implement such a modification.

In one embodiment of FIG. 2, the UE can only receive the beacon signaland cannot send a probe request message nor receive the probe response.In another embodiment, the UE can only send the probe request messageand receive the probe response and cannot receive the beacon signal. Inother embodiments, the UE can receive a beacon signal and can also senda probe request message and receive a probe response. In this lastimplementation, the UE can determine whether to send the probe requestbased on previous beacon signals.

As described above, the source-to-target container transmitted from theLTE eNodeB to the MME can include the IP address of the target WLAN AGW.Although the above description considered the case in which the IPaddress is included in the message received at S210, the IP address canalso be determined by the LTE eNodeB based on other information includedin the message. Alternatively, another device participating in theforwarding of the source-to-target container (e.g., the MME, a defaultWLAN AGW, etc.) can determine the IP address. In addition, the LTEeNodeB, the MME, or the default AGW need not actually perform thedetermination itself and can instead transmit information to anotherdevice that actually performs the determination and transmits the IPaddress back to the LTE eNodeB, the MME, or the default WLAN AGW.

In one example of the WLAN→LTE handover discussed previously, the UEtransmits LTE eNodeB parameters to the WLAN AP via an 802.11 MACmessage, the WLAN AP sends a handover message to the WLC via enhancedCAPWAP, the WLC sends a handover message to the WLAN AGW via S1-AP-Lite,and the WLAN AGW communicates parameters to the MME. In anotherimplementation, the WLC sends a handover message to the MME, rather thansending a handover message to the WLAN AGW via S1-AP-Lite and the WLANAGW sending the handover message to the MME.

In the handovers discussed above, it was explained the WLAN AGW keepsmapping information in a database to identify the WLAN AP or the WLCusing a MAC address and/or location information of the WLAN AP. Althoughthat database is typically kept in the WLAN AGW, the database can alsobe located at a different device, in which case the WLAN AGW transmitsinformation to that device, which then replies to the WLAN AGW with theidentity of the WLAN AP or the WLC.

With regard to the WLAN→LTE handover, the default MME can be replacedwith a database running on a server. When the WLAN AGW transmits theeNodeB ID to the default MME, the server can look up the eNodeB in thedatabase and respond to the WLAN AGW with an identify of the target MME.

Specific bit patterns were provided with respect to, for example, the802.11 MAC messages sent by the UE to the WLAN AP in a WLAN→LTEhandover. These bit patterns were provided by way of example only, andit is specifically contemplated that different bit patterns can be used.

This disclosure was written from the point of view of anacknowledgment-based protocol. The present teachings are not so limited,as it is specifically contemplated that the teachings can be modified tocomply with a negative-acknowledgement protocol (or protocols).

The teachings of the present disclosure are applicable to Macro LTE toSP/Enterprise WLAN handover, SP/Enterprise WLAN to Macro LTE handover,small cell LTE to WLAN handover, WLAN to small cell handover, homescenarios, and 3G-WLAN handover, but are no means limited thereto.

Numerous other changes, substitutions, variations, alterations, andmodifications can be ascertained by one skilled in the art, and it isintended the present disclosure encompasses all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims. To assist the United StatesPatent and Trademark Office (USPTO) and, additionally, any readers ofany patent issued on this application in interpreting the claimsappended hereto, Applicant wishes to note the Applicant: (a) does notintend any of the appended claims to invoke 35 U.S.C. section 112(f) asit exists on the date of the filing hereof unless the words “means for”or “step for” are specifically used in the particular claims; and (b)does not intend, by any statement in the specification, to limit thisdisclosure in any way that is not otherwise reflected in the appendedclaims.

1-20. (canceled)
 21. A computer-implemented method, comprising:receiving, in a wireless local area network, an identifier of a basestation in a cellular network; contacting a first device in the cellularnetwork via a tunnel; receiving an identity of a second device in thecellular network; establishing, by a processor, a tunnel with the seconddevice; transmitting, using a specified protocol and the tunnel, theidentifier of the base station to the cellular network; receiving, usingthe tunnel, a first indication whether a handover from the wirelesslocal area network to the cellular network is accepted; and transmittinga second indication in the wireless local area network that the handoveris accepted.
 22. The computer-implemented method of claim 21, furthercomprising: determining an identity of the first device based at leastin part on a location of a device in the wireless local area network.23. The computer-implemented method of claim 21, further comprising:determining an identity of the first device based at least in part onmapping information in a database.
 24. The computer-implemented methodof claim 21, further comprising: transmitting to the first device aQuality of Service (QoS) parameter of a session in the wireless localarea network.
 25. The computer-implemented method of claim 21, whereinthe first device is a database server or a mobility management entity.26. The computer-implemented method of claim 21, further comprising:transmitting to the first device using an LTE_WLAN Handover (LWH)interface.
 27. A non-transitory computer-readable medium embedded with acomputer executable program including instructions that, when executedby a processor, cause the processor to perform an operation comprising:receiving, in a wireless local area network, an identifier of a basestation in a cellular network; contacting a first device in the cellularnetwork via a tunnel; receiving an identity of a second device in thecellular network; establishing, by the processor, a tunnel with thesecond device; transmitting, using a specified protocol and the tunnel,the identifier of the base station to the cellular network; receiving,using the tunnel, a first indication whether a handover from thewireless local area network to the cellular network is accepted; andtransmitting a second indication in the wireless local area network thatthe handover is accepted.
 28. The non-transitory computer-readablemedium of claim 27, the operation further comprising: determining anidentity of the first device based at least in part on a location of adevice in the wireless local area network.
 29. The non-transitorycomputer-readable medium of claim 27, the operation further comprising:determining an identity of the first device based at least in part onmapping information in a database.
 30. The non-transitorycomputer-readable medium of claim 27, the operation further comprising:transmitting to the first device a Quality of Service (QoS) parameter ofa session in the wireless local area network.
 31. An access gateway,comprising: a processor; and a memory containing a program executable bythe processor to perform an operation comprising: receiving, in awireless local area network, an identifier of a base station in acellular network; contacting a first device in the cellular network viaa tunnel; receiving an identity of a second device in the cellularnetwork; establishing a tunnel with the second device; transmitting,using a specified protocol and the tunnel, the identifier of the basestation to the cellular network; receiving, using the tunnel, a firstindication whether a handover from the wireless local area network tothe cellular network is accepted; and transmitting a second indicationin the wireless local area network that the handover is accepted. 32.The access gateway of claim 31, the operation further comprising:determining an identity of the first device based at least in part on alocation of a device in the wireless local area network.
 33. The accessgateway of claim 31, the operation further comprising: determining anidentity of the first device based at least in part on mappinginformation in a database.
 34. The access gateway of claim 31, theoperation further comprising: transmitting to the first device a Qualityof Service (QoS) parameter of a session in the wireless local areanetwork.
 35. The computer-implemented method of claim 21, wherein theidentifier of the base station is received in a first 802.11 mediaaccess control (MAC) message including a frame control field in whichthe type is set to 01 and in which the subtype is set to 0000; whereinthe first indication comprises an acknowledgement message, theacknowledgment message comprising a second 802.11 MAC message includinga frame control field in which the type is set to 01 and in which thesubtype is set to 0001; wherein the second indication comprises a third802.11 MAC message including a frame control field in which the type isset to 01 and in which the subtype is set to
 0010. 36. Thecomputer-implemented method of claim 35, each 802.11 MAC message havinga format that includes a frame control field of two bytes, a durationidentifier field of two bytes, a destination address field of six bytes,a source address field of six bytes, a basic service set identifierfield of six bytes, a sequence control field of two bytes, an addressfield of six bytes, a quality of service control field of two bytes, aframe body, and frame check sequence field of four bytes; wherein thesequence control field facilitates identifying message ordering andremoving duplicate frames, wherein the frame body is between zero and2,312 bytes, wherein the frame control field includes a protocol versionfield of two bits, a type field of two bits, a subtype field of fourbits, a to-distribution-system field of one bit, afrom-distribution-system field of one bit, a more-fragments field of onebit, a retry field of one-bit, a power management field of one bit, amore-data field of one bit, a protected-frame field of one bit, and anorder field of one bit.
 37. The computer-implemented method of claim 36,wherein the specified protocol is based on S1 Application Protocol(S1-AP), wherein the first indication includes a RACH preamble, whereinthe first device is, in respective instances, a database server and amobility management entity, wherein the computer-implemented methodfurther comprises: determining an identity of the first device based atleast in part on, in respective instances: (i) a location of a device inthe wireless local area network; and (ii) mapping information in adatabase; transmitting to the first device a Quality of Service (QoS)parameter of a session in the wireless local area network; stopping atransmission of data in the wireless local area network after thetransmitting the second indication; and transmitting to the first deviceusing an LTE_WLAN Handover (LWH) interface.
 38. The computer-implementedmethod of claim 37, wherein the tunnel comprises a first tunnel, whereinthe computer-implemented method is to implement wireless local areanetwork (WLAN) to long-term evolution (LTE) handover, wherein thecomputer-implemented method further comprises performing an operation toimplement LTE to WLAN handover, the operation comprising: receiving, inthe cellular network, a first identifier of a wireless network accesspoint of the wireless local area network; transmitting, in the cellularnetwork, the first identifier of the wireless network access point;establishing a second tunnel to the wireless local area network;transmitting a second identifier of the wireless network access pointover the second tunnel; and transmitting in the cellular network thesecond identifier of the wireless network access point, in response toreceiving from the wireless local area network the second identifier ofthe wireless network access point.
 39. The computer-implemented methodof claim 38, wherein the operation further comprises: transmitting anidentification of a scheduling gap; receiving a signal strength of asignal from the wireless network access point during the scheduling gap;receiving a network address of a third device in the wireless local areanetwork, wherein the second tunnel is established to the device in thewireless local area network; performing an association for the wirelesslocal area network in the cellular network; performing an authenticationfor the wireless local area network in the cellular network; andforwarding buffered data to the wireless local area network aftertransmitting the second identifier in the cellular network.
 40. Thecomputer-implemented method of claim 39, wherein the network addresscomprises an Internet Protocol (IP) address, wherein thecomputer-implemented method further comprises: receiving, in respectiveinstances during the scheduling gap, a predefined message selected fromeach of: (i) a beacon signal and (ii) a probe response message; whereineach of the beacon signal and the probe response message includes atimestamp field, a beacon interval field, and a set of vendor-specificextension fields, the set of vendor-specific extension fields including:(i) a wireless local area network (WLAN) access point (AP) locationfield; (ii) a WLAN AP MAC address field containing any WLAN AP MACaddress that differs from a basic service set identifier (BSSID) used ina 802.11 MAC frame header; (iii) a WLAN access gateway (AG) IP addressfield; and (iv) a wireless LAN controller (WLC) network address field;wherein the beacon signal further includes a quality-of-servicecapability field; wherein the probe response message further includes anEnhanced Distributed Channel Access (EDCA) parameter set field and arequested information elements field, wherein the probe response messageis received in response to a probe request message.